vt discuss
Office: BTV
FXUS61 KBTV 030554
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
154 AM EDT Fri May 3 2024
.SYNOPSIS...
After lingering showers in far northeastern Vermont wind down,
dry conditions in the wake of a cold front will continue
overnight. Some low clouds and fog will be possible overnight,
then skies should become partly to mostly sunny on Friday. Some
rain showers will enter northern New York on Saturday, and the
entire region for Sunday. Aside from the cooler and wetter
weather on Sunday, largely seasonable weather is expected over
the next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 151 AM EDT Friday...No major changes were needed to the
forecast with this update, only some minor tweaks were made to
reflect recent observations. Clouds cover has been increasing a
bit as light northeasterly flow has become more dominant and
these clouds should linger for much of the night. Fog has been
developing in some of the sheltered valleys, particularly in the
areas that saw some rain yesterday. Previous discussion
follows..
Previous Discussion... A cluster of rain showers is currently
skirting through far northeastern Vermont late this afternoon.
It is associated with a cold pool aloft as heights fall in the
base of the upper trough swinging southeastward behind the
surface cold front that is now well east of our region. The
pressure gradient behind the front is weak such that winds have
only been around 10 to 15 MPH, and the northwesterly winds
should diminish, as will any lingering light rain
showers/sprinkles, after sunset.
While anticyclonic flow will lead to continued dry weather
overnight, the question remains as to how much fog and/or low
stratus develops. Expect our mountains to be obscured by low
clouds overnight due to a subsidence inversion and lingering
moisture. Otherwise, have offered patchy fog largely where it
rained this afternoon/early evening in northern/northeastern
Vermont. However, conditionally areas of fog will develop in
portions of northern New York where skies clear out. Compared to
areas farther east, 925 millibar flow looks particularly light
overnight. In contrast, light southeasterly flow suggests
stratus will be more prominent east of the Green Mountains.
For Friday into Friday night, no significant weather is expected
with ridging building into our region. Temperatures have trended
a touch warmer, with most likely highs now exceeding 70 in just
about all of the Champlain Valley in addition to the St.
Lawrence Valley. The aforementioned southeasterly flow will
dampen warming in central and eastern Vermont a bit, but it
should be a largely pleasant day once morning shallow clouds
dissipate. Towards the very end of the period shower chances
develop across our western areas, but there is quite a bit of
model disagreement on if the upper level forcing is sufficient
to get enough lift to support precipitation. The incoming wave
looks to peter out as it runs into a strong ridge, so mainly we
will see increasing cloud cover and mild temperatures with an
increase in southerly wind Friday night.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
As of 323 PM EDT Thursday...PWATs rise to 2 standard deviations above
normal on Sunday as moisture with Gulf of Mexico origin looks to
overspread the region. Forecast soundings show a lack of surface-
based instability, so showers with brief locally heavy downpours
look to be the main risk. While there could be embedded thunder due
to elevated instability, no organized thunderstorms are anticipated.
It will be quite breezy as well, with persistent southeast winds
gusting 30-35 mph at times. Rainfall chances wise, it does look like
areas east of the Adirondacks should stay dry for most of Saturday.
This is because while a shortwave trough moves eastward from the
Great Lakes, it encounters a stout omega block, and therefore the
best forcing is diverted north of our region on Saturday. While
there should be plenty of cloud cover, have utilized the 75th
percentile of model guidance for Champlain Valley and point east.
Highs should top out right around 70, or a few degrees above
climatological norm for early May across the Champlain Valley.
Expect 60s elsewhere, except 50s in the high terrain. Heading into
Sunday, the omega block finally moves east, allowing the shortwave
trough to approach closer to our CWA albeit in a deamplified state.
This means that PoPs increase to the likely category with scattered
to perhaps numerous showers on Sunday. While there would likely be
widespread wetting rainfall, QPF amounts are quite manageable in the
0.25 to 0.5 inch range. Indeed, the MMEFS shows none of our area
rivers going into action stage.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 323 PM EDT Thursday...The overall weather pattern heading into
the first full week of May can be described as unsettled with no
real significant warm up or impactful weather. Unsurprisingly, the
CPC 8-14 day temperature outlook favors near normal temperatures and
leans towards above normal rainfall. For reference, typical highs
for North Country in early May are in the low to mid 60s, while
average overnight lows are in the mid 30s to low 40s. The upper
level pattern features a positively tilted omega block sandwiched
between an anomalously deep trough across the Rockies/northern Great
Plains and another trough over eastern Quebec/Newfoundland. H5
height anomalies favor a period of widespread showers and
thunderstorms in the Tuesday/Wednesday time frame, as positive H5
height anomalies give way to near normal values. Depending on the
timing of the associated surface cold front, ingredients may exist
for a few stronger storms. But with the potential storms being 5
days away, have largely stuck to a blend of guidance for this time
frame.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Through 12Z Friday...Ceilings have been gradually lowering this
evening and should continue to do so overnight. Confidence is
relatively high that ceilings will reach IFR at BTV while confidence
is lower whether ceilings will reach IFR at PBG and MPV. EFK and SLK
should hold onto their low clouds and fog overnight before it scours
out after daybreak. However, the IFR cloud deck at SLK could briefly
scatter out a couple times overnight. The IFR ceilings at RUT are
expected to remain the entire night but there is lower confidence
there. Ceilings will rise quickly after daybreak and all terminals
should be VFR by late morning. There should only be high clouds
during the day today but the clouds will begin to lower and thicken
tonight, though they should remain VFR for the first part of the
night. Winds are relatively light and are generally northerly but
they should transition to southerly during the day tomorrow. LLWS is
not a concern.
Outlook...
Saturday: VFR. Chance SHRA.
Saturday Night: VFR. Chance SHRA.
Sunday: Mainly VFR, with areas MVFR possible. Likely SHRA.
Sunday Night: MVFR/IFR conditions possible. Chance SHRA.
Monday: Mainly VFR, with areas MVFR possible. Slight chance SHRA.
Monday Night: VFR. NO SIG WX.
Tuesday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Kutikoff
NEAR TERM...Kutikoff/Myskowski
SHORT TERM...Chai
LONG TERM...Chai
AVIATION...Myskowski
